AC Apparatus & Devices

September 30, 2017 | Author: Brian Kim Benoza | Category: Relay, Fuse (Electrical), Transformer, Switch, Electrical Equipment
Share Embed Donate

Short Description

AC Apparatus & Devices...


Brian Kim N. Benoza BSEE-4th year In the design of electrical power systems, the ANSI standard device numbers (ANSI /IEEE Standard C37.2 Standard for Electrical Power System Device Function Numbers, Acronyms, and Contact Designations ) identifies the features of a protective device such as a relay or circuit breaker. These types of devices protect electrical systems and components from damage when an unwanted event occurs, such as an electrical fault. Device numbers are used to identify the functions of devices shown on a schematic diagram. Function descriptions are given in the standard. One physical device may correspond to one function number, for example "29 Isolating Switch", or a single physical device may have many function numbers associated with it, such as a numerical protective relay. Suffix and prefix letters may be added to further specify the purpose and function of a device. ANSI/IEEE C37.2-2008 is one of a continuing series of revisions of the standard, which originated in 1928. ANSI Device Numbers Apparatus 

1 – Master Element

2 – Time Delay Starting or Closing Relay

3 – Checking or Interlocking Relay

4 – Master Contactor

5 – Stopping

6 – Starting Circuit Breaker

7 – Rate of Change Relay

14 – Underspeed Device 15 – Speed – or Frequency, Matching Device

16 – Data Communications Device

17 – Shunting or Discharge Switch

18 – Accelerating or Decelerating Device

19 – Starting to Running Transition Contactor

8 – Control Power Disconnecting Device

20 – Electrically Operated Valve

9 – Reversing Device

21 – Distance Relay

10 – Unit Sequence Switch

22 – Equalizer Circuit Breaker

11 – Multi-function Device

23 – Temperature Control Device

12 – Overspeed Device

24 – Volts Per Hertz Relay

13 – Synchronous-speed Device

25 – Synchronizing or SynchronismCheck Device

26 – Apparatus Thermal Device

27 – Undervoltage Relay

46 – Reverse-phase or Phase-Balance Current Relay

47 – Phase-Sequence or Phase-Balance Voltage Relay

28 – Flame detector

29 – Isolating Contactor or Switch

30 – Annunciator Relay

31 – Separate Excitation

32 – Directional Power Relay or Reverse Power Relay

33 – Position Switch

34 – Master Sequence Device

35 – Brush-Operating or Slip-Ring ShortCircuiting Device

36 – Polarity or Polarizing Voltage Devices

48 – Incomplete Sequence Relay 49 – Machine or Transformer, Thermal Relay 50 – Instantaneous Overcurrent Relay

50G - Instantaneous Earth Over Current Relay (Neutral CT Method)

50N - Instantaneous Earth Over Current Relay (Residual Method)

50BF - Breaker failure

51 – AC Inverse Time Overcurrent Relay

51G- AC Inverse Time Earth Overcurrent Relay (Neutral CT Method)

51N- AC Inverse Time Earth Overcurrent Relay (Residual Method)

37 – Undercurrent or Underpower Relay

38 – Bearing Protective Device

39 – Mechanical Condition Monitor

40 – Field (over/under excitation) Relay

41 – Field Circuit Breaker

52a- AC Circuit Breaker Position (Contact Open when Breaker Open)

42 – Running Circuit Breaker

52b- AC Circuit Breaker Position (Contact Closed when Breaker Open)

43 – Manual Transfer or Selector Device

53 – Exciter or DC Generator Relay

44 – Unit Sequence Starting Relay

54 – Turning Gear Engaging Device

45 – Abnormal Atmospheric Condition Monitor

55 – Power Factor Relay

56 – Field Application Relay

52 – AC Circuit Breaker

57 – Short-Circuiting or Grounding Device

58 – Rectification Failure Relay

59 – Overvoltage Relay

60 – Voltage or Current Balance Relay

61 – Density Switch or Sensor

62 – Time-Delay Stopping or Opening Relay

77 – Telemetering Device

78 – Phase-Angle Measuring Relay or "Out-of-Step" Relay

79 – AC Reclosing Relay (Auto Reclosing)

80 – Flow Switch

81 – Frequency Relay

82 – DC Reclosing Relay

63 – Pressure Switch

64 – Ground Detector Relay

64R - Restricted earth fault

64S - Stator earth fault

65 – Governor

86 – Lockout Relay/Master Trip

66 – Notching or Jogging Device

87 – Differential Protective Relay

67 – AC Directional Overcurrent Relay

88 – Auxiliary Motor or Motor Generator

68 – Blocking Relay

89 – Line Switch

69 – Permissive Control Device

90 – Regulating Device

70 – Rheostat

91 – Voltage Directional Relay

71 – Liquid Level Switch

92 – Voltage and Power Directional Relay

72 – DC Circuit Breaker

93 – Field Changing Contactor

73 – Load-Resistor Contactor

94 – Tripping or Trip-Free Relay

74 – Alarm Relay

96 – Busbar Trip Lockout relay

75 – Position Changing Mechanism

150 – Earth Fault Indicator

76 – DC Overcurrent Relay

 

83 – Automatic Selective Control or Transfer Relay 84 – Operating Mechanism 85 – Communications,Carrier or PilotWire Relay

ANSI Devices used in 5 MVA Transformers Fuses and switchgear E-rated power fuses are typically used in fused switches serving transformers. The purpose of the fuse is to allow for full use of the transformer and to protect the transformer and cables from faults. To accomplish this, the fuse curve should be to the right of the transformer inrush point and to the left of the cable damage curve. Typically, the fuse will cross the transformer damage curve in the long time region (overcurrent region). The secondary main device provides overcurrent protection for the circuit. “E” fuse ratings should always be greater than the transformer full load amps (FLA). The cable damage curve must be above the maximum fault current at 0.01 s. For transformers 3 MVA and less, standard overcurrent protection schemes for MV switchgear breakers should include an instantaneous and overcurrent combination relay (device 50/51). For transformers greater than 5 MVA, protection schemes become more complex. IEEE device numbers from IEEE C37.2 are used to outline the protection scheme. Transformer MV breakers may include the following protective device numbers: In MV systems, current transformers (CTs) connect protective or metering devices. CTs interface the electronic device and the MV primary system. The MV primary system voltage and current levels are dangerously high and cannot be connected directly to a relay or meter. The CTs provide isolation from the cable’s high voltage and current levels and translate the primary current to a signal level that can be handled by delicate relays/meters. The rated secondary current is commonly 5 amp, though lower currents such as or 1 amp are not uncommon. Protective relay’s CTs are expected to deliver about 5 amps or less under healthy load conditions. The current will go to a high value when a fault occurs. Per ANSI C57.13, normal protective CT class secondary should withstand up to 20 times for a short period of times under fault conditions. As a consequence, protective class CTs are accurate enough to drive a set of indication instruments, but will not be good enough for revenue class summation energy metering.

View more...


Copyright ©2017 KUPDF Inc.